PURPOSE: The assessment of possibility to add a new indication for the registered pharmaceutical. Evaluation of safety and efficacy of Visomitin® compared to placebo in patients with age-related cataracts. METHODS: A randomized, double-blind, placebo-controlled clinical study of Visomitin® eye drops in patients with age-related cataracts was conducted in accordance with Good Clinical Practice guidance, the Declaration of Helsinki and the Russian regulatory requirements. The study included 80 patients (23 men and 57 women) aged 45 to 75 years with diagnosed age-related cataract. All subjects were randomized into two groups of 40 patients each. In the treatment group patients received Visomitin® eye drops and in the control group, patients were given placebo (vehicle, i.e. eye drops with the same composition as Visomitin® except for the active substance SkQ1) in the form of instillations of one drop per each eye three times daily for six months. The study comprised 7 monthly visits. The following standard ophthalmological examinations were used to evaluate the effectiveness of the therapy: visual acuity measurement, refractometry, biomicroscopy of the eye, ophthalmoscopy, tonometry, computer perimetry, densitometry. At certain visits lacrimal fluid was taken for evaluation of its antioxidant activity. Blood pressure and heart rate were measured as a part of safety evaluation which also included documentation of complaints and adverse events. Concomitant therapies were also documented. RESULTS: Analysis of safety parameters showed Visomitin® to be safe and well tolerated for patients with age-related cataract. Practically no adverse effects were documented during the study. In both groups a decrease of the number of patients with subjective complaints was observed. These complaints included: visual deterioration, dryness, grittiness, burning eyes, eye fatigue. The decrease of the number of complaints in the Visomitin® group was more pronounced than in the placebo group. During the first months of treatment an improvement of visual acuity was observed in both groups. This result can be explained by a protective effect of hypromellose contained in both Visomitin® and placebo. However, between the 4th and the 6th months, the improvement in visual acuity significantly slowed down in the placebo group, while positive dynamics remained the same in the Visomitin® group. At the end of the treatment visual acuity increased by more than 50% in Visomitin® group and remained at the level of 10-15% in the placebo group (statistically significant difference between placebo and Visomitin® groups, p<0.05). Even more pronounced difference was detected for older patients, where placebo did not cause any increase in visual acuity (p<0.001 at the end of the treatment). A tendency for decrease of the mean and maximum density of the lens was found in the group of patients treated with Visomitin®. On the contrary in the placebo group both mean and maximum density of the lens tended to increase. It is reasonable to suggest that these effects of Visomitin® resulted from an increase of antioxidant protection of eye that was verified by the measurement of the antioxidant activity of lacrimal fluid in the study. After 6 months of treatment antioxidant activity of lacrimal fluid significantly increased in the group of patients treated with Visomitin® compared to that in the placebo group. CONCLUSION: Study results support the use of Visomitin® as effective and safe treatment of age-related cataract. Such treatment can be aimed at deceleration of the disease progression in order to delay surgery. The study results allowed adding a new indication for the use of Visomitin® eye drops.